Abstract
The mass application of lithium-ion batteries will inevitably lead to the accumulation of a huge amount of battery waste. Recycling scrapped batteries offer a means to alleviate environmental damage, resource depletion, and waste accumulation. Especially since the lithium content of waste batteries is much higher than the mineable grade of lithium ores, recycling it will bring huge economic benefits. Yet, the overall recovery rate of lithium from these secondary resources is still less than 1%. To ameliorate this situation, a multi-stage method for direct selective leaching of lithium from industrial-grade, mixed lithium-ion battery waste is proposed, so as to efficiently realize the selective leaching and enrichment of lithium. Through the combined action of formic acid and hydrogen peroxide, the single stage leaching rate of lithium can exceed 97%, while leaching rates of impurity metals such as nickel, cobalt, manganese, copper, aluminum, and iron remain below 1%. The multi-stage leaching process developed in this method increases the concentration of lithium in the leachate from 1.8 g/L to 7.9 g/L, maintaining Li leaching efficiency above 95%. The advantages of this method are high lithium leaching efficiency, exceptional selectivity, simple operation under ambient conditions, and environmental friendliness. Moreover, this method avoids complex and lengthy powder separation steps, reducing the cost and consumption of energy. This method can be applied to a variety of different compositions of Li-ion battery waste, with excellent industrial application prospects.